ＦＢＡＲ只是让他们报告国外财产不是缴税

报告财产不一定是缴税。你父母现在居住在美国，享受美国国防司法警察服务，让他们缴税都没有什么错误，现在ＦＢＡＲ只是让他们报告国外财产，你抱怨什么？

In summary

(1) your parents does not need to PAY TAX on their Chinese pension, according to Sino-US tax treaty

(2) Your parents need to file FBAR and FAICA forms to REPORT foreign asset, not pay tax.

http://www.irs.gov/Businesses/Comparison-of-Form-8938-and-FBAR-Requirements

(2.1) 8938 form, 国外财产超过５万美元（包括房产） 以后卖房赚钱要缴税

(2.2) FBAR reporting 国外银行账户超过１万美元 以后存款股票赚了钱要缴税。